Semiconductor package form within an encapsulation

ABSTRACT

Provided are a semiconductor package which is small in size but includes a large number of terminals disposed at intervals equal to or greater than a minimum pitch, and a method of fabricating the semiconductor package. The semiconductor package includes a semiconductor chip having a bottom surface on which a plurality of bumps are formed, redistribution layer patterns formed under the semiconductor chip and each including a first part electrically connected to at least one of the bumps and a second part electrically connected to the first part, an encapsulation layer surrounding at least a top surface of the semiconductor chip, and a patterned insulating layer formed below the redistribution layer patterns and exposing at least parts of the second parts of the redistribution layer patterns.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device, and moreparticularly, to a semiconductor package for protecting a semiconductorchip and connecting the semiconductor chip with an external device.

2. Description of the Related Art

As the integration density of semiconductor chips increases, the numberof pads of each semiconductor chip increases. However, semiconductorpackages are being continuously demanded to be smaller and lighter withan increasing demand for portable semiconductor products. For example, achip scale package (CSP) can reduce the size of a semiconductor packageby forming terminals on pads of a semiconductor chip.

However, the terminals of the CSP are required to be large enough toform a stable electrical contact with an external device and to beseparated from one another by suitable pitches. For example, when theterminals of the CSP are connected to an external device by solderballs, and the pitch between terminals is less than or equal to apredetermined value, the solder balls may adhere to each other. Forexample, JEDEC standards prescribe a minimum pitch between theterminals.

The JEDEC Solid State Technology Association (once known as the JointElectron Device Engineering Council), is the semiconductor engineeringstandardization body of the Electronic Industries Alliance (EIA), atrade association that represents all areas of the electronics industry.JEDEC was originally created in 1960 as a joint activity between EIA anNEMA, to cover the standardization of discrete semiconductor devices andlater expanded in 1970 to include integrated circuits. JEDEC establishesstandards for the spacing of external contacts that lead into integratedcircuit and semiconductor device packages. Spacing of the externalcontacts are important because suppliers of die attach equipment andsoldering equipment must know the spacing between the contact leads orpads of a circuit of a device into to attach the circuit or device to aprinted circuit board so that the soldered contacts do not interferewith each other.

However, a decrease in the number of pads of each semiconductor chiprequires an increase in the number of terminals of the CSP. Hence, it isdifficult to form an increased number of terminals spaced from eachother at a predetermined pitch on a small semiconductor chip. As aresult, the terminals may extend up to the outside of the semiconductorchip, and thus additional wires for connecting the pads on thesemiconductor chip to the terminals may be needed.

For example, U.S. Pat. No. 6,001,671, issued to Fjelstad, discloses asemiconductor package in which conductive pads are used as terminals anda semiconductor chip is connected to the terminals by wire bonding.

However, a method of manufacturing the semiconductor package, which isdisclosed in U.S. Pat. No. 6,001,671, is complicated because it requiresa wire bonding process. Also, in the method, the conductive pads canonly be disposed around the semiconductor chip, thus enlarging thesemiconductor package.

SUMMARY OF THE INVENTION

The present invention provides a semiconductor package which is small insize but includes a large number of terminals disposed at intervalsequal to or greater than a minimum pitch.

The present invention also provides a method of fabricating thesemiconductor package.

According to an aspect of the present invention, there is provided asemiconductor package including: a semiconductor chip comprising a topsurface and a bottom surface, the bottom surface having a plurality ofbumps formed thereon; redistribution layer patterns formed under thesemiconductor chip, comprising a first part electrically connected to atleast one of the bumps and a second part electrically connected to thefirst part; a patterned insulating layer formed below the redistributionlayer patterns, exposing at least a part of the second part of theredistribution layer patterns; and an encapsulation layer exposing abottom surface of the patterned insulating layer and surrounding thesemiconductor chip, the bumps, and the redistribution layer patterns.

The semiconductor package may further include an organic insulatinglayer interposed between the redistribution layer patterns and thesemiconductor chip, having conductive particles distributed in theorganic insulating layer. The first parts of the redistribution layerpatterns may be electrically connected to the bumps by the conductiveparticles of the organic insulating layer.

The bumps may directly contact the first parts of the redistributionlayer patterns.

According to another aspect of the present invention, there is provideda method of fabricating a semiconductor package, including theoperations of: forming a semiconductor chip comprising a top surface anda bottom surface, the bottom surface having a plurality of bumps formedthereon; forming a sacrificial substrate on which redistribution layerpatterns comprising first parts facing the bumps and second partselectrically connected to the first parts are formed; disposing thesemiconductor chip over the sacrificial substrate on which theredistribution layer patterns are formed, and electrically connectingthe bumps to the first parts of the redistribution layer patterns;forming an encapsulation layer on the sacrificial substrate to surroundthe semiconductor chip on which the redistribution layer patterns areformed; removing the sacrificial substrate so that the redistributionlayer patterns are exposed; and forming a patterned insulating layerbelow the exposed redistribution layer patterns, the patternedinsulating layer exposing at least parts of the second parts of theredistribution layer patterns.

In the operation of electrically connecting the bumps to the first partsof the redistribution layer patterns, an organic insulating layer havingconductive particles distributed therein may be used.

In the operation of electrically connecting the bumps to the first partsof the redistribution layer patterns, the bumps may be physically bondedto the first parts of the redistribution layer patterns.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIG. 1 is a cross-section of a semiconductor package according to anembodiment of the present invention;

FIG. 2 is a bottom view of the semiconductor package of FIG. 1;

FIG. 3 is a plan view of a sacrificial substrate on which redistributionlayer patterns are formed;

FIGS. 4 through 8 are cross-sectional views illustrating a method ofmanufacturing the semiconductor package of FIG. 1;

FIG. 9 is a cross-section of a semiconductor package according toanother embodiment of the present invention; and

FIGS. 10 through 13 are cross-sectional views illustrating a method ofmanufacturing the semiconductor package of FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more fully with reference tothe accompanying drawings, in which exemplary embodiments of theinvention are shown. The invention may, however, be embodied in manydifferent forms and should not be construed as being limited to theembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the concept of the invention to those skilled in the art. In thedrawings, the thicknesses of layers and regions are exaggerated forclarity.

FIG. 1 is a cross-section of a semiconductor package 100 according to anembodiment of the present invention. FIG. 2 is a bottom view of thesemiconductor package 100. FIG. 1 may be a cross-section taken alongline I-I′ of FIG. 2.

Referring to FIG. 1, a plurality of bumps 110 are formed on a bottomsurface of a semiconductor chip 105. For example, the bumps 110 may beformed on metal pads (not shown) of the semiconductor chip 105. Themetal pads are electrically connected to unit elements (not shown)formed therebelow. The bumps and metal pads provide input and outputterminals for connecting the chip 105 to other chips. The internalstructure of the semiconductor chip 105 may vary, and accordingly doesnot limit the scope of the present invention. For example, thesemiconductor chip 105 may include a memory device or various types oflogic circuits.

The number of bumps 110 may depend on the number of metal pads, whichmay vary according to the integration density of the semiconductor chip105. For example, as the integration density of the semiconductor chip105 increases, the number of metal pads increase, and accordingly, thenumber of bumps 110 may increase. The bumps 110 may include a conductivematerial, such as, copper or gold. The bumps 110 may have any shape aslong as it protrudes from the bottom surface of the semiconductor chip105.

The bumps 110 are electrically connected to redistribution layerpatterns 120. The redistribution layer patterns 120 are conductivemembers that may serve as terminals which are connected to an externaldevice. Each of the redistribution layer patterns 120 includes a bumpcontact pattern 122 and a land pattern 124, which are electricallyconnected to each other. For example, the land pattern 124 may serve asa terminal which is connected to an external device, and the bumpcontact pattern 122 may connect the bump 110 to the land pattern 124.The bump contact pattern 122 and the land pattern 124 are connected by aconductive line 126.

The redistribution layer patterns 120, which are formed on a sacrificialsubstrate 128 of FIG. 4, will now be described in greater detail withreference to FIG. 3. The redistribution layer patterns 120 redistributerandomly distributed bumps 110 so that the bumps 110 can be connected tothe external device. The redistribution layer patterns 120 may also beused to extend the pitch between adjacent bumps 110. In this case, theland patterns 124 may have a larger pitch than the bump contact patterns122. For example, although the bump contact patterns 122 do not have aJEDEC standard pitch, the land patterns 124 may have the JEDEC standardpitch.

The shape of the redistribution layer patterns 120 shown in FIG. 1 isjust an example, but the bump contact patterns 122 and the land patterns124 may have various shapes and be disposed in various configurations.For example, in contrast with FIG. 1, the land patterns 124 may bedistributed inside and outside the bump contact patterns 122.

Furthermore, a surface area of each of the land patterns 124 is largerthan that of each of the bump contact patterns 122. Hence, by using theland patterns 124 as terminals, a sufficient area of contact with theexternal device can be secured. Each of the redistribution layerpatterns 120 may be a gold layer, a nickel layer, a copper layer, or acomplex layer which is a stack of at least one of these layers. Forexample, the redistribution layer pattern 120 may be a complex layerformed by stacking a gold layer, a nickel layer, a copper layer, anickel layer, and a gold layer.

Referring back to FIG. 1, the bumps 110 and the bump contact patterns122 are electrically connected to each other by an organic insulatinglayer 115 in which conductive particles 17 are distributed. For example,the electrical connection of the bumps 110 with the bump contactpatterns 122 may be achieved in such a way that a bump 110 and a bumpcontact pattern 122 are commonly connected to at least one of theconductive particles 117. The organic insulating layer 115 may includean anisotropic conductive film (ACF), an anisotropic conductive paste(ACP), and an anisotropic conductive adhesive (ACA). The conductiveparticles 117 may include metal particles, for example, gold particles,copper particles, or nickel particles, or particles obtained by platingpolymer beads with gold.

Referring to FIGS. 1 and 2, a patterned insulating layer 135 is formedbelow the redistribution layer patterns 120, more specifically, belowthe organic insulating layer 115 that exposes the redistribution layerpatterns 120. The insulating layer 135 has holes 140 through which atleast parts of the land patterns 124 are exposed. For example, theinsulating layer 135 may include a solder resist layer or a polyimidelayer.

The exposed parts of the land patterns 124 may electrically contact theexternal device. For example, the exposed parts of the land patterns 124may be electrically connected to the external device via solder balls.Although the holes 140 are formed outside the semiconductor chip 105 inFIG. 1, they may be distributed inside and outside the semiconductorchip 105 according to the configuration of the land patterns 124.

A pitch between exposed land patterns 124 may be greater than thatbetween bumps 110 or metal pads. Hence, the bump contact patterns 122,facing the bumps 110, may extend using the land patterns 124 having alarger pitch. Thus, the semiconductor package 100 can be reliablyconnected to an external device having connection pads (not shown)having a larger pitch than the bumps 110 by using the land patterns 124.In addition, the semiconductor package 100 can be reduced in size bydepositing the bumps 100 and the redistribution layer patterns 120 underthe semiconductor chip 105. In other words, the semiconductor package100 may have a CSP structure.

An encapsulation layer 130 covers the semiconductor chip 105 below whichthe redistribution layer patterns 120 and the patterned insulation layer135 are formed. The encapsulation layer 130 protects the semiconductorchip 105 from external environments.

FIGS. 4 through 8 are cross-sectional views illustrating a method ofmanufacturing the semiconductor package 100 of FIG. 1. The structure ofthe semiconductor package 100 may be described with reference to FIGS. 1through 3 and corresponding previous descriptions.

Referring to FIG. 4, the semiconductor chip 105 having the plurality ofbumps 110 formed thereon is prepared for. The bumps 110 may be formed onthe semiconductor chip 105 in a method similar to wire bonding. Thebumps 110 help the metal pads of the semiconductor chip 105 to protrudeto the outside. Additionally, the bumps 110 may have good adhesion withthe metal pads. Accordingly, the bumps 100 should be at least 5 μm largeand may be less than several hundreds of μm so as to achieve stable flipchip bonding. For example, the diameter of each of the bumps 110 mayrange from 10 μm to 200 μm.

Aside from the formation of the bumps 110 on the semiconductor chip 105,the sacrificial substrate 128 having the redistribution layer patterns120 formed thereon is provided. The redistribution layer patterns 120and the sacrificial substrate 128 may be understood from thedescriptions of FIGS. 1 and 3. The sacrificial substrate 128 having theredistribution layer patterns 120 formed thereon may be commerciallymanufactured by plating or other processes.

The sacrificial substrate 128 may be formed of a material having etchselectivity with respect to the redistribution layer patterns 120. Thesacrificial substrate 128 may be a metal layer, such as, a copper layeror an aluminum layer. As described above, the redistribution layerpatterns 120 may be covered with a gold layer.

Referring to FIG. 5, the bumps 110 are electrically connected to theredistribution layer patterns 120 by the organic insulating layer 115 inwhich the conductive particles 117 are distributed. More specifically,the bumps 110 are electrically connected to the bump contact patterns122 by one or more of the conductive particles 117.

For example, the organic insulating layer 115 may be inserted betweenthe bottom surface of the semiconductor chip 105 and the sacrificialsubstrate 128, more specifically; between the bumps 110 and theredistribution layer patterns 120. The organic insulating layer 115 maybe formed before or after flip chip bonding. Thereafter,thermo-compression is applied to the semiconductor chip 105 or theredistribution layer patterns 120, so that each of the bumps 110 andeach of the redistribution layer patterns 120 can commonly contact atleast one of the conductive particles 117. Hence, reliable electricalconnection between the redistribution layer patterns 120 and the bumps110 can be achieved.

Referring to FIG. 6, the encapsulation layer 130 is formed on thesacrificial substrate 128 to surround the semiconductor chip 105 havingthe redistribution layer patterns 120 formed thereon. The encapsulationlayer 130 may be epoxy or encapsulating molding compound (EMC). Theencapsulation layer 130 protects the semiconductor chip 105 from achemical reaction, such as, external physical impact and moisture.

Referring to FIGS. 6 and 7, the sacrificial substrate 128 is removed sothat the redistribution layer patterns 120 can be exposed. For example,only the sacrificial substrate 128 may be etched without etching theredistribution layer patterns 120. The gold layer coated on theredistribution layer patterns 120 protects the redistribution layerpatterns 120 from etching.

Referring to FIG. 8, the patterned insulating layer 135 is formed belowthe redistribution layer patterns 120 which are exposed. Morespecifically, the patterned insulative layer 135 having the holes 140through which parts of the land patterns 124 are exposed is formed belowthe organic insulating layer 115 which exposes the redistribution layerpatterns 120. For example, an insulating layer (not shown) may be formedbelow the organic insulating layer 115, and the holes 140 may be formedby patterning the insulating layer using photolithography and an etchingtechnique.

FIG. 9 is a cross-section of a semiconductor package 200 according toanother embodiment of the present invention. The semiconductor package200 is a modification of the semiconductor package 100. Hence,descriptions of identical or similar parts of the semiconductor packages100 and 200 will be omitted, and only differences will now be described.Like reference numerals in the two semiconductor packages 100 and 200denote like elements.

Referring to FIG. 9, the bumps 110 directly contact the redistributionlayer patterns 120. More specifically, the bumps 110 and the bumpcontact patterns 122 are physically bonded together to be electricallyconnected to each other.

An encapsulation layer 130 a covers the top surface and lateral surfacesof the semiconductor chip 105. The encapsulation layer, 130 a may befurther interposed between the bottom surface of the semiconductor chip105 and the redistribution layer patterns 120 and between the bottomsurface of the semiconductor chip 105 and the patterned insulating layer135. In this case, the encapsulation layer 130 a may be a single layeror a complex layer. For example, the encapsulation layer 130 a may be asingle layer, such as, an EMC layer or an epoxy layer.

Alternatively, the top surface and lateral surfaces of the semiconductorchip 105 may be covered with an EMC layer or an epoxy layer, and asolder resist layer or a polyimide layer may be interposed between thebottom surface of the semiconductor chip 105 and the redistributionlayer patterns 120 and between the bottom surface of the semiconductorchip 105 and the patterned insulating layer 135.

The semiconductor package 200 may have the advantages of thesemiconductor package 100. For example, the pitch between land patterns124 may be greater than that between bumps 110 or metal pads. Thus, byusing the semiconductor package 200, terminals, namely, the landpatterns 124, may have an appropriate pitch. In addition, thesemiconductor package 200 can be reduced in size by depositing the bumps110 and the redistribution layer patterns 120 under the semiconductorchip 105. In other words, the semiconductor package 200 may have a CSPstructure.

FIGS. 10 through 13 are cross-sectional views illustrating a method ofmanufacturing the semiconductor package 200 of FIG. 9. The method ofFIGS. 10 through 13 is described with reference to the method of FIGS. 4through 8. Like reference numerals in the two methods denote likeelements.

Referring to FIG. 4, the semiconductor chip 105 having the plurality ofbumps 110 formed on the bottom surface thereof is provided. After orbefore the preparation of the semiconductor chip 105, the sacrificialsubstrate 128 having the redistribution layer patterns 120 formedthereon is provided. A detailed description of the sacrificial substrate128 can be made with reference to the method of FIGS. 4 through 8, so itis omitted.

Referring to FIG. 10, the bumps 110 directly contacts the bump contactpatterns 122. For example, the bumps 110 may be physically bonded to thebump contact patterns 122. More specifically, the semiconductor chip 105and the redistribution layer patterns 120 come close to each other sothat the bumps 110 can contact the bump contact patterns 122.Thereafter, thermosonic waves are applied to the semiconductor chip 105and the redistribution layer patterns 120 which are close to each other.Hence, the redistribution layer patterns 120 and the bumps 110 whichcontact with each other can be bonded to each other and electricallyconnected to each other.

Referring to FIG. 11, the encapsulation layer 130 a is formed on thesacrificial substrate 128 to surround the semiconductor chip 105 and theredistribution layer patterns 120. The encapsulation layer 130 a may bea single layer or a complex layer as described above with reference toFIG. 9.

Referring to FIG. 12, the sacrificial substrate 128 is removed so thatthe redistribution layer patterns 120 can be exposed. The removingmethod is the same as described above in the previous method.

Referring to FIG. 13, the patterned insulating layer 135 is formed belowthe redistribution layer patterns 120 which are exposed. Morespecifically, the patterned insulatiive layer 135 having the holes 140through which parts of the land patterns 124 are exposed is formed belowthe encapsulation layer 130 a which exposes the redistribution layerpatterns 120. As described above, the patterned insulating layer 135 maybe formed using photolithography and an etching technique.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

1. A semiconductor package comprising: a semiconductor chip comprising atop surface and a bottom surface, the bottom surface having a pluralityof bumps formed thereon; redistribution layer patterns formed under thesemiconductor chip, comprising a first part electrically connected to atleast one of the bumps and a second part electrically connected to thefirst part; a patterned insulating layer formed below the redistributionlayer patterns, exposing at least a part of the second part of theredistribution layer patterns; an encapsulation layer exposing a bottomsurface of the patterned insulating layer and surrounding thesemiconductor chip, the bumps, and the redistribution layer patterns;and an organic insulating layer interposed between the redistributionlayer patterns and the semiconductor chip, having electricallyconductive particles distributed in the organic insulating layer,wherein the electrically conductive particles are interposed between topsurfaces of the first parts of the redistribution layer patterns andbottom surfaces of the bumps to directly contact the top surfaces offirst parts of the redistribution layer patterns and the bottom surfacesof the bumps.
 2. The semiconductor package of claim 1, wherein a surfacearea of the second part of each of the redistribution layer patterns isgreater than a surface area of the first part of each of theredistribution layer patterns.
 3. The semiconductor package of claim 1,wherein a diameter of each of the bumps is in the range of 5 to 200 μm.4. The semiconductor package of claim 1, wherein each of theredistribution layer patterns comprises one or more layers of the groupconsisting of a gold layer, a nickel layer, and a copper layer.
 5. Thesemiconductor package of claim 1, wherein the second parts of theredistribution layer patterns are land patterns to be connected to anexternal device.